Did your winter season just passes, and you want to open it and you are wondering how much shock is necessary? Is there a separate shocking mechanism for pools about to be opened after winter? How much shock is needed?
These questions and more will be duly answered in this article. Stay with me. First, let us start with what shocking means, and the essence of shocking to a swimming pool.

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What is Shock?
Anyone who knew this term might think it is related to electricity. No, it is not so. The act of shocking the pool simply means adding necessary chemicals to the swimming pool.
The essence of doing this is to separate chloramines, increase the level of chlorine in the swimming pool, and then kill algae.
The major essence of shocking is to break down the chloramines. There is 3 kind of chlorine in the pool. They are free chlorine, combined chlorine, and total chlorine.
Free chlorine, as it sounds, is free. It is free in relation to algae, bacteria, other chemicals, etc. it destroys bacteria, algae, and other things that can harm the swimming pool.
Then there is combined chlorine, which is joined with something. The joining is not a healthy one. The joining is mostly either with ammonia or nitrogen.
Now, that is joined with another, the chlorine finds it hard to move around the swimming pool like when it was free. This makes it lose its ability to kill bacteria, algae, etc.
Now, the most annoying or worst thing about this state is that chlorine can remain in this state as long as there is no external assistance in breaking away from the ammonia or nitrogen.
How can the combined chlorine be helped externally? It is done by adding more free chlorine or oxidizer. Now, let me clarify this. When you go to a swimming pool, and you think you smell chlorine, what you smell is combined chlorine, not free chlorine.
The last is the total chlorine. This one seems complex. It is the combo of both free and combined chlorine.
Read: How Much Clorox Shock For 1000 Gallon Pool
Why Shocking?
The purpose of shock is to free chlorine from its combined state. Now, the decision to use a chlorinated or non-chlorinated shocker will be dependent on the level of chlorine in your swimming pool at that moment.
Another important reason why we shock is to sanitize the swimming pool, by increasing the level of chlorine which is the sanitizer.
The recommended level of chlorine in a swimming pool is 3 parts per million.
The shocker can also be used as means to eradicate algae. Shocking your swimming pool is not just a one-time thing; it is something that needs to be done frequently.
To determine how frequently you need to be doing this, you will have to consider things like the period of rains and sunshine, bather load and frequency, dust, etc.
But there is a general rule as to how frequent you need to shock your swimming pool, it is once a week.
To open your swimming pool after the winter season, shocking is necessary to raise the chlorine level to 6 parts per million. Algae cannot survive in this environment.
It is advisable to use a 50% – 95% calcium hypochlorite shock to raise the level of chlorine in your swimming pool.
Can I Shock My Swimming Pool When Opening it?
You might be wondering if it is a necessity at all. Well, you should shock your swimming pool when you are opening it after the season. This will hike the chlorine level to the recommended level, as I earlier explained.
It will also kill and destroy algae that might have built up during the season. Note that you might not notice algae always.
Normally, your swimming pool should have a chlorine level of about 3-6 parts per million. If there are many algae in the swimming pool, you might need to up it to 5-6 parts per million.
How You Can Know How many shocks You Need to Open a Swimming Pool
The shock you will add to open your swimming pool is heavily dependent on the concentration of the calcium hypochlorite and the brand that made the shock you are purchasing.
Here is what I mean. Some brands can produce a bag of shock that is designed to treat 3000 gallons of the pool, while another brand produces a bag of shock designed to shock 5000 gallons of the pool.
Considering this, it is really important to read instructions when buying your shocker.
The level of your chlorine in your swimming pool after the season is a strong determinant.
There are specific instances where chlorine lost due to evaporation will be little or next to nothing because the swimming pool was well covered. Covers like solar covers disallow the evaporation of chlorine, and it maintains the shock treatment.
If the chemical level of the swimming pool is well maintained during the season and you notice that the swimming is clear and free of algae, there might not be any reason to shock the swimming pool beside the necessary weekly shocking.
Be careful though, you might not be able to see the algae sometimes.
When Should I Shock My Swimming Pool after Opening it?
How to know when to proceed with shocking after opening your swimming pool might be confusing. Here are little pointers that can help
A chlorine level lesser than 4 parts per million.
One of the essences of shock is to increase the chlorine level in the swimming pool or to free chlorine. If you notice that the chlorine level of your swimming pool is going down, you must shock.
The presence of algae
I am sure you know that shocking can eliminate the presence of algae in your swimming pool. Any observation or detection of algae in your swimming pool might need action like shocking.
The look of the swimming pool.
The way the swimming pool water looks is not something to overlook. If the pool water looks green, cloudy, or colored, you might need to result to shocking.
The situation
You might know beforehand that you might be having a lot of people using your swimming pool. It might be important to shock the swimming pool in this instance.
There is a warning you need to take note of. You need to be careful when shocking. There is such a thing as doing too much with the shock. It is referred to as over-shocking.
Is it Possible to Over-Shock?
This is very much possible. I mentioned earlier the range of levels of chlorine needed in a swimming pool. If you shock your swimming pool, causing a rise in chlorine level to about 7 parts per million, that is over-shocking.
Having too much chlorine in your swimming pool has a lot of effects. It can lead to skin irritation, spoil some pool equipment and also corrode the pool liner.
Chlorine is a harsh chemical, if exposed too much to the skin or the eyes can cause irritation.
If you end up over-shocking your pool, it may look too cloudy. This is a result of the powdered state of the shock. Immediately after shocking, the pool may look a little cloudy, don’t get it mixed up, but with over-shocking, the cloudiness will be stronger.
If you feel you have gone way far with the shocking, don’t fret. It is not irreversible. Remove your pool solar cover. Then add water to dilute the concentration of the chlorine in the swimming pool.
If you stick to just the regular weekly shocking, you won’t have to deal with the issue of over-shocking.
How Long Will It take for the Swimming Pool to be clear after Shocking?
After shocking your swimming pool, it should only take a few hours before it clears up. It will take the dead algae in the swimming pool a few days before it is cleared up.
If you want it to be faster than that, you can just get your filter cleaned and make use of a water clarifier in your swimming pool.
What it does is that it hikes the density of the fiber’s micron. This then results in the easy elimination of remnants or debris in the swimming pool. Read more
Final Thoughts
There are checks and balances to the level of shocking that can be involved in opening your pool which has been detailed in this article.